Age and Great Invention Review of Economics and Statistics, forthcoming
Abstract: Great achievements in knowledge are produced by older innovators today than they were a century ago. Using data on Nobel Prize winners and great inventors, I find that the mean age at which noted innovations are produced has increased by 6 years over the 20th Century. I estimate shifts in life-cycle productivity and show that innovators have become especially unproductive at younger ages. Meanwhile, the later start to the career is not compensated for by increasing productivity beyond early middle age. I further show that the early life-cycle dynamics are closely related to variation in the age at Ph.D. and discuss a theory where accumulations of knowledge across generations lead innovators to seek more education over time. More generally, the results show that individual innnovators are productive over a narrowing span of their life cycle, a trend that reduces, other things equal, the aggregate output of innovators. This drop in productivity is particularly acute if innovators' raw ability is greatest when young.